The Voigtländer & Sohn Flachkamera (Radiar) is a flat-bodied plate camera from the early decades of the twentieth century, fitted with a Radiar lens. It was sold as a compact folding-style instrument for amateur and travel photography during the era when Voigtländer & Sohn operated as a German-Austrian optical manufacturer.

Auction evidence for this model is thin, with a single recorded UK saleroom hammer result of £400 in November 2021. On that limited basis, what a Flachkamera (Radiar) is worth today sits around the £400 mark at auction-hammer level, though buyers should treat that figure as indicative rather than a settled market price given how rarely the camera sells.